A new form of near-field scanning optical microscopy (NSOM) for studying electric-field-induced dynamics in highly localized regions within birefringent thin film materials is presented. The method is applied to dynamics studies of polymer-dispersed liquid crystal (PDLC) films. A sinusoidally modulated voltage is applied between the NSOM probe and a conductive substrate upon which the PDLC film is supported. A concentrated electric field is formed within the film directly beneath the probe. Time-dependent molecular motion induced by this field is observed via crossed-polarized, transmitted-light near-field optical methods. It is shown that dynamics in volumes as small as 10(-15) cm(3) may be probed using this method. Via lock-in detection of the optical signal, amplitude and phase images of the local dynamics are recorded. Contrast in these images is utilized to better understand the local-field-induced reorientation process. Information on both the path through which the molecules reorient and spatial variations in the time scale for reorientation is obtained.